I highly recommend hosting anything more intensive than the Remote Access web site with a hosting provider. First, Windows Home Server is not designed for such use, so configuring an additional gallery web site is unsupported. Next, you probably don't have a great deal of upstream bandwidth; most broadband connections are asymmetric. So your site may be extremely slow. Finally, hosting this on your home broadband connection may be against your ISP's terms of service.
If you really want to proceed anyway, not storing your data in the shares is the right thing to do. If you have a lot of data, you should add a drive to your server, but don't add it to the storage pool. Then you can use that drive for your web site. If you have a small amount of data, you could put it in a folder you create on D:, in which case it will show up as part of the System wedge of the storage pie chart. In either case, you will have to manage everything yourself; Windows Home Server won't manage shares, permissions, etc. for you.
I'm not on the WHS team, I just post a lot. :)
